LT1076-5

1

10765fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

5V Step-Down

Switching Regulator

switching regulator which requires only a few external parts

for normal operation. The power switch, all oscillator and

control circuitry, all current limit components, and an output

monitor are included on the chip. The topology is a classic

positive “buck” configuration but several design innova-

tions allow this device to be used as a positive-to-negative

converter, a negative boost converter, and as a flyback con-

verter. The switch output is specified to swing 40V below

ground, allowing the LT1076-5 to drive a tapped inductor

in the buck mode with output currents up to 4A.

The LT1076-5 uses a true analog multiplier in the feedback

loop. This makes the device respond nearly instantaneously

to input voltage fluctuations and makes loop gain indepen-

dent of input voltage. As a result, dynamic behavior of the

regulator is significantly improved over previous designs.

On-chip pulse by pulse current limiting makes the LT1076-

5 nearly bust-proof for output overloads or shorts. The

input voltage range as a buck converter is 8V to 60V, but

a self-boot feature allows input voltages as low as 5V in

the inverting and boost configurations.

The LT1076-5 is available in a low cost 5- and 7-lead TO-

220 packages with frequency pre-set at 100kHz and current

limit at 2.6A. See Application Note 44 for design details.

Basic Positive Buck Converter

5V

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

LT1076-5

SENSE

GND

R3

1.5k

C2

0.033

μF

C3

200

μF

100

MBR340*

MBR330P MAY BE USED

COILTRONICS #100-1-52

HURRICANE #HL-AG210LL

VALUE MAY BE REDUCED TO 50

μH

FOR OUTPUT LOADS BELOW 1.5A

8V TO 40V

C1

500

μF

25V

LT1076-5 TA01

5V

≤1.8A

*

**

†

+

+